Many aerospace components include air channels (e.g., for cooling) that are fabricated to strict specifications and tested during manufacture to ensure that fluid flow and differential pressure across these channels fall within expected ranges. Part-specific sealing molds are used throughout the airflow testing process to cover and restrict airflow through the air channels. Current molds can be a cast rubber formed around a scrap component to obtain the desired geometry. Further features can be added by cutting away the material. Mold making can be a time-consuming process, and the molds are prone to leaking if improperly cast or cut.